Korean -지만 vs -는데: When -는데 Isn't "But" at All

Here is the one thing to take away: -지만 contrasts two facts. -는데 sets up a situation so the next sentence makes sense.

Dictionaries translate both as "but," and that translation is what trips learners up. -지만 really is "but." -는데 is "but" maybe a third of the time — the rest of the time it's closer to "so," "and," "just so you know," or nothing at all in English. If you treat them as interchangeable, your Korean stays grammatical but sounds strangely argumentative, like you're contradicting yourself every other sentence.

Let's fix the forms first, then the feeling.

The forms

-지만 is the easy one. Attach it straight to the stem. No irregulars to worry about, no verb/adjective split.

-는데 changes shape depending on what it attaches to:

• Verbs → -는데 (가는데, 먹는데)
• Adjectives → -(으)ㄴ데 (좋은데, 바쁜데)
• 있다/없다 → -는데 (재미있는데, 없는데) — they behave like verbs here
• 이다 → -ㄴ데 (학생인데, 친구인데)
• Past tense → always -는데 (갔는데, 좋았는데, 학생이었는데)

Two spots that catch people: ㅂ-irregular adjectives (맵다 → 매운데, 춥다 → 추운데) and ㄹ-stem verbs, which drop the ㄹ (살다 → 사는데, 만들다 → 만드는데). And both endings attach with no space — see our notes on Korean spacing rules if that's still shaky.

-지만: a real contrast, and that's all

-지만 joins two complete facts that pull against each other. A is true, B is also true, and B is surprising given A. Both halves carry equal weight.

• 한국어는 어렵지만 재미있어요. — Korean is hard, but it's fun.
• 가격은 비싸지만 맛은 좋아요. — The price is high, but the taste is good.
• 커피를 마셨지만 계속 졸려요. — I drank coffee, but I'm still sleepy.

Notice the shape of these: a clean A-versus-B, the kind of sentence you'd write in an essay or say when you're making a point. -지만 is slightly more written, slightly more formal, and very tidy. Korean also loves it in a handful of fixed polite prefaces:

• 실례지만 지금 몇 시예요? — Excuse me, but what time is it?
• 죄송하지만 지금은 좀 어려울 것 같아요. — I'm sorry, but that'll be difficult right now.
• 미안하지만 오늘은 못 갈 것 같아요. — Sorry, but I don't think I can come today.

Those three are worth memorizing whole. They're everywhere in polite 해요체 speech.

One limit: -지만 cannot end a sentence. If you want "But..." at the start of a new sentence, that's 하지만 (neutral/written) or 그런데 / 근데 (spoken).

-는데: the stage, then the point

Now the one that matters more, because it's far more common in speech. With -는데, the first clause isn't a competing fact — it's background. You're handing the listener the information they need before you say the real thing.

• 비가 오는데 우산 있어요? — It's raining — do you have an umbrella?
• 내일 시간 있는데 같이 점심 먹을래요? — I'm free tomorrow — want to get lunch?
• 이거 좀 매운데 괜찮으세요? — This is a bit spicy — is that okay?
• 어제 그 식당에 갔는데 사람이 진짜 많았어요. — I went to that restaurant yesterday, and there were so many people.

Try putting "but" into any of those. "It's raining but do you have an umbrella?" is nonsense. The rain is the reason for the question, not a contrast with it. That's -는데 doing its real job.

Here's a test that works most of the time: if you could replace "but" with "so," "and," or a dash, you want -는데. If only "but" fits and the two halves genuinely clash, -지만 is safe.

-는데 is also the standard way to soften a request or an opener. Walk up to a stranger and you'll hear this shape constantly — along with the openers in our guide to how to address strangers in Korean:

• 저기요, 뭐 좀 여쭤보고 싶은데요. — Excuse me, I'd like to ask you something.

That trailing -는데요 is another thing -지만 can't do. Left hanging at the end of a sentence, it means "...and I'll let you fill in the rest."

• 저는 매운 거 잘 못 먹는데요. — I can't really eat spicy food, though... (= so maybe pick something else)
• 오늘은 좀 피곤한데요. — I'm a bit tired today, though...

It's soft, a little indirect, and extremely Korean. If you want more on how -는데 plays with the other connectors, we compared it with -아서 and -(으)니까 in this guide to connecting Korean sentences.

Same sentence, two feelings

Sometimes both are grammatical. The difference is what you're doing socially.

• 한국에서 3년 살았지만 아직 한국어를 잘 못해요. — I lived in Korea for three years, but I still can't speak Korean well.
• 한국에서 3년 살았는데 아직 한국어를 잘 못해요. — I lived in Korea for three years, and I still can't speak Korean well...

The first is a statement. It closes. The second opens a door — it sounds confiding, a bit rueful, and it invites the other person to respond ("아, 그래요?"). In conversation, Koreans pick the second far more often. -지만 in casual chat can land as oddly formal, like you're reading from a report.

And -는데 can carry real contrast too, usually with an edge of "and yet?":

• 이 가방 비싼데 왜 샀어요? — This bag is expensive — why did you buy it?
• 커피를 마셨는데 계속 졸려요. — I drank coffee, and I'm still sleepy.

The mistakes that sound wrong

1. Using -지만 when nothing contrasts. This is the big one.

• ✗ 제가 지금 밖에 있지만 이따 전화해도 될까요?
• ✓ 제가 지금 밖에 있는데 이따 전화해도 될까요? — I'm out right now — can I call you later?

Being outside isn't the opposite of calling later. To a Korean ear the -지만 version sounds like you've mixed up two unrelated thoughts.

2. Forgetting that adjectives take -(으)ㄴ데. ✗ 좋는데, ✗ 바쁘는데 → ✓ 좋은데, 바쁜데. (But 있다/없다 keep -는데: 맛있는데, 시간 없는데.)

3. Trying to end a sentence with -지만. It doesn't work. Use 하지만 or 근데 to start the next sentence instead.

4. Wall-to-wall -지만 in speech. Three -지만 sentences in a row make you sound like you're arguing. Spoken Korean runs on -는데.

One more thing to watch: -는데 is neutral about politeness on its own, so the speech level lives on the final verb. 비가 오는데 우산 있어? is 반말, 비가 오는데 우산 있어요? is 해요체. If that distinction is new, start with Korean speech levels.

Practice

Fill in the blank with the correct form of -지만 or -는데.

1. 날씨가 (좋다) ___ 같이 산책할까요?
2. 어제 명동에 (가다, past) ___ 사람이 정말 많았어요.
3. 한국어 문법은 (어렵다) ___ 발음은 쉬워요.
4. Fix this: 제가 지금 좀 바쁘지만 나중에 다시 전화해도 될까요?
5. 이 찌개 좀 (맵다) ___ 괜찮으세요?